Three-dimensional spin–orbit coupled Fermi gases: Fulde–Ferrell pairing, Majorana fermions, Weyl fermions, and gapless topological superfluidity |
Zero-temperature phase diagram with an anisotropic spin–orbit coupling and equal in-plane and out-of-plane Zeeman fields h in = h out = h . The Rashba spin–orbit coupling corresponds to the case with θ = π /4. The color map shows the lowest energy in the particle branches, in units of E F . Here, we use a spin–orbit coupling strength λ = E F/ k F and an interaction strength 1/( k F a s) = −0.5. |